Prevalence of Gastrointestinal Parasites in Wild Asian Elephants (Elephas maximus) at a National Park in Eastern Thailand

Abstract

Protected national parks continue to face increased pressure from the expansion of human–wildlife interface zones, where habitat encroachment promotes human–wildlife contact and zoonotic disease transmission. Gastrointestinal parasites (GIPs) are a significant health issue in wild Asian elephants (Elephas maximus), affecting their fitness, survival, and potential for cross-species transmission. This study aimed to investigate the prevalence of GIPs among wild elephants at Khao Sip Ha Chan National Park in eastern Thailand. Direct smear, formalin-ethyl acetate sedimentation, flotation, and McMaster egg per gram (EPG) counting were used to examine 135 fecal samples from three populations. The findings showed that nematodes (Strongyle-type and Strongyloides spp.) and trematodes (Paramphistomum spp. and Fascioloides jacksoni) were identified. All samples were positive for at least one parasite species, and 84.4% were affected by mixed infections. The prevalence of Strongyle-type and Strongyloides spp. varied significantly among the studied populations, but Paramphistomum spp. had a moderate prevalence, and Fascioloides jacksoni had a low prevalence. The high parasite burden could be explained by environmental factors, host density, and movement patterns influencing parasite transmission, and these factors should be further investigated. These findings provide crucial baseline data and underscore the need for integrated parasite surveillance, alongside long-term conservation and future research.